| Bacillus lipopeptide metabolites have a variety of biological activities,such as antibacterial,anti-tumor and anti-virus,but the yield of bacillus lipopeptide is generally low.Exploring the cultivation conditions of high yield is the focus of development and utilization,while the rapid yield evaluation method can greatly improve the efficiency of condition exploration.In this paper,on the basis of the previous successful screening of a strain of bacillus cereus WK1 which has obvious inhibiting effect on this pathogenic bacteria,the optimal fermentation time of bacillus amylogenes WK1 was analyzed in depth,the method to evaluate its yield was explored,and the optimal fermentation process was found by using HPLC to quantify the yield of its lipopeptide antibiotics.The best fermentation time to explore.Bacillus WK1,as a bacillus species,has obvious inhibition effect on b.othidea,the pathogen of dry rot of pecans.Through 48,60 and 72 hours in three different time of shaking flask fermentation metabolites get antibiotics,making the solid medium containing antibacterial substances,bacteria will grape cavity B.d othidea pathogens of single-celled vaccination to all the medium containing antibiotics are unable to grow,and pathogens cake vaccination to medium containing antibiotics,can be the difference between the inhibition rate of inhibition effect was observed,the best fermentation time of 72 h.A new method for rapid evaluation of bacillus bacillus lipopeptide yield and substrate carbon utilization efficiency was developed.Taking Bacillus amyloliquefaciens WK1 as the experimental strain,different initial pH(5,6,7)was designed to incubate to produce antibacterial lipopeptides of different yield(concentration).The difference of lipopeptide yield between the gravimetric method and the differential subtraction method showed the same rule,namely pH6>pH7>pH5,and the number of related systems of the two methods was 0.5632(n=9),but the values obtained by the differential subtraction method under the same initial pH condition were higher than those obtained by the gravimetric method.Microbial lipopeptide production efficiency and carbon dioxide emission were the lowest under pH5,and the carbon dioxide emission per unit culture medium(700 C mg· kg-1)at the initial pH6 was the same as that under pH7,but the lipopeptide production yield(1228 mg· l-1 medium)and lipopeptide production efficiency(234 mg· kg-1 OC)were the highest under pH6.Conclusion differential subtraction is a simple,rapid and effective method to evaluate lipopeptide yield.Optimization of antibiotic production conditions of WK1 strain.Through different types of culture medium(Landy medium and NA culture medium),quantity(3% and 5%),the initial pH values(5,6,and 7)found in WK1 strains for fermentation process,the fat peptide antibiotics,NA medium fat peptide antibiotics than Landy medium high,5% quantity of output 3% quantity of high,pH6 yield higher than the pH7 above pH5.For polyketones,the yield of Landy medium was higher than that of NA medium,the yield of 3% inoculation volume was higher than that of 5% inoculation volume,and the yield of pH6 was higher than that of pH7 and higher than that of pH5.All medium conditions,lipid production of peptide antibiotics were significantly higher than the material gathered ketones,think in terms of lipid peptide material production should choose NA culture medium,due to early weight method preliminary evaluation medium effects on crude extractings from fat peptide found that production of Landy medium was obviously higher than that of NA culture medium,so there is no to NA inoculation amount and initial pH of culture medium in the experiment,the need to continue to explore.The optimal conditions for polyketogenic substances of WK1 were Landy medium,3% inoculation amount and initial pH6(300mL in bottle). |
